The present invention relates to a method for controlling a reagent delivery system in an automatic chemical analyzer for automatically analyzing various components in a number of samples such as bloods and urines.
Nowadays, various automatic chemical analyzers have been installed in test sections in many hospitals and laboratories and a great amount of accurate analyzing results have been obtained in a speedy manner. Particularly, multi-item automatic chemical analyzers which can measure a number of test items, for example, thirty test items, have been developed and practically used. In known multi-item automatic chemical analyzers, a given reagent to be used for a revelant test item is selected from among a number of necessary reagents for testing a number of test items and a given amount of the selected reagent is delivered by a specialized delivery device in order to avoid possible contamination between reagents of different kinds. That is to say, since each of different reagents are processed by respective delivery devices, there occurs no contamination between the different reagents. However, in such a reagent delivery system, the number of the delivery devices has to be equal to that of the reagents of different kinds. For instance, when thirty different kinds of reagents are to be used in the analyzer, the analyzer should include thirty delivery devices which are operable independently from each other. This results in a large analyzing apparatus that is complicated in construction and expensive in cost. A reagent delivery system in which only those portions which are made in contact with the reagents are provided by the same number as that of the different reagents and any one of them is selectively coupled with a main body of the reagent delivery device has also been proposed. For instance, there are provided a number of probes or nozzles which are selectively connected to a syringe by means of a switching valve. However, in such a system, since the probes must be changed at a middle of a liquid path, liquid leakage is liable to occur and thus, the accuracy of reagent delivery might be decreased. Moreover, the larger number of different kinds of required reagents, the more complicated the construction of the reagent delivery system becomes. Another proposal was to deliver all of the different kinds of reagents by means of a single delivery device. However, in such a system, in order to avoid or decrease the contamination between the different reagents, the delivery device must be washed in a special manner. Thus, it is necessary to provide a special washing device of high efficiency which requires a large amount of a washing liquid and thus, it is also necessary to prepare or stock a large amount of the washing liquid. This results in that the analyzer is liable to be large in size.